1. Field of the Invention
This disclosure relates to a sheet conveying apparatus having a moving member capable of guiding a sheet, a drive transmission apparatus and an image forming apparatus.
2. Description of the Related Art
In general, in an image forming apparatus configured to form images on both sides of a sheet, when image formation on a first side is terminated, the sheet is switched back and is conveyed to a duplex conveying path for being re-conveyed to the image forming portion. At this time, the sheet is reliably conveyed to the duplex conveying path by using a moving member configured to be capable of switching a conveyance route of the sheet. Recently, simplification of the image forming apparatus is desired for downsizing and power saving of the image forming apparatus.
In contrast, in an image forming apparatus disclosed in Japanese Patent Laid-Open No. 2007-76881, simplification of the apparatus is achieved by driving a moving member configured to switch the conveyance route of the sheet by using the same drive source configured to rotate only in one direction, and a conveyance roller configured to discharge the sheet out of the machine or switch back and convey the sheet to the duplex conveying path.
Specifically, the above-described image forming apparatus is configured to rotatably support a swinging gear on the moving member, and switch a drive transmission route from the drive source to a discharge roller depending on the position of the swinging gear swinging together with the moving member configured to be pivoted by a solenoid, so that the conveyance roller is configured to be forwardly and reversely rotatable.
Japanese Patent Laid-Open No. 2006-56627 discloses an image forming apparatus configured to distribute a drive force of one motor into the conveyance roller and the moving member configured to switch a conveyance path of the sheet, and including a one way hinge having a torque limiter function arranged in a power transmission route from the motor to the moving member.
In the image forming apparatus, the moving member is driven and abuts against an abutting portion, so that the one way hinge functions as the torque limiter to prevent an excess load from being applied to the moving member, whereby the moving member is positioned.
However, in the image forming apparatus described in Japanese Patent Laid-Open No. 2007-76881, a relatively large force is required in the solenoid in order to maintain the swinging gear rotatably supported by the moving member in a state of engaging other gears or to disengage the swinging gear from other gears.
In the image forming apparatus disclosed in Japanese Patent Laid-Open No. 2006-56627, an idling torque of the one-way hinge needs to be set to be sufficiently larger than an inertia moment of the moving member. Therefore, when the moving member abuts against the abutting portion, a torque is continuously applied to the moving member until exceeding the idling torque, and hence energy loss occurs. Therefore, the image forming apparatus of the related art needs a relatively large energy for driving the conveyance roller and the moving member.